From my experience the traditional style exhaust ( not true dual ) with decats or hfc will rasp . I had a scorpion with hfc and it was chav tastic , really raspy . Then swooped to invidia ... No rasp but slight drone on the motorway . Then I went decats and miltek system ... Again loads of rasp .... Change to the art pipes ( decat with side resonator ) a lot less rasp , no drone ..... Almost too quite !! I've now bought another invidia to pair with the art pipes and hope this to be the winning combo !! Gets fitted tomorrow so will let you know !!
My best guess would be for you to get the art pipes .... Quieter than the hfc and good gains .... Only down side is you need a friendly mot place .'
Or buy an invidia !